Heart rate measuring device

Abstract

The invention relates to a heart rate measuring apparatus and a method, adapted for measuring a subject's ( 6 ) heart rate and/or heart rate variation. The heart rate measuring apparatus ( 1 ) comprises a holder ( 2 ) adapted for carrying a portion of a body part of the subject ( 6 ) lying on or resting against the holder ( 2 ), a motion sensor ( 4 ) operatively connected to the holder ( 2 ), wherein the holder ( 2 ) is adapted for being at least partly moveable in a horizontal direction relative to the ground ( 7 ), the motion sensor ( 4 ) being adapted for measuring a signal generated by a movement of the subject ( 6 ) at least partly in the horizontal direction. In this way, a reliable signal is obtained adapted for measuring the heart rate and/or heart rate variation of a subject while keeping the implementation costs low.

The invention claimed is: 
     
       1. A heart rate measuring apparatus, adapted for measuring a subject's heart rate and/or heart rate variation, comprising:
 a holder adapted for carrying at least a portion of a body part of the subject lying on or resting against the holder, and 
 a motion sensor operatively connected to the holder, 
 wherein the holder is adapted for being at least partly moveable in a horizontal direction relative to the fixed world, and 
 the motion sensor is adapted for measuring a signal generated by a movement of the subject at least partly in the horizontal direction relative to the fixed world upon movement of the holder relative to the fixed world, and 
 the motion sensor including an electrical motion sensor having a capacitor with an electrical capacitance formed between a first electrode and a second electrode, the first electrode being fixed relative to the fixed world and the second electrode being fixed relative to the holder, at least one of the first and second electrodes being movable relative to the other of the first and second electrodes. 
 
     
     
       2. The heart rate measuring apparatus according to  claim 1 , further comprising a monitoring system operatively connected to the motion sensor, wherein the monitoring system is adapted to receive the signal from the motion sensor and is adapted to generate from the signal, information about the subject's heart rate and/or heart rate variation, and is further adapted to relay the information about the subject's heart rate and/or heart rate variation to a user. 
     
     
       3. The heart rate measuring apparatus according to  claim 1 , wherein the capacitor includes a oscillator circuit, the output of which is a frequency signal modulated by the heart rate. 
     
     
       4. The heart rate measuring apparatus according to  claim 1 , further comprising a scale adapted for determining the force and/or weight of the subject in a direction at least partly perpendicular to the fixed world. 
     
     
       5. The heart rate measuring apparatus according to  claim 1 , wherein the holder comprises a suspension structure adapted for allowing a movement of the holder at least partly in the horizontal direction. 
     
     
       6. The heart rate measuring apparatus according to  claim 5 , wherein the holder comprises a bed, a mattress, a cushion, a crib and/or an incubator. 
     
     
       7. The heart rate measuring apparatus according to  claim 5 , wherein the suspension structure includes a spring. 
     
     
       8. Use of the heart rate measuring apparatus according to  claim 1 , wherein the heart rate and/or heart rate variation is adapted to be measured for monitoring applications, and/or the heart rate and/or heart rate variation are used to determine the occurrence of a heart failure, wherein, upon determination of the heart failure, the heart rate measuring apparatus generates an alarm signal. 
     
     
       9. The heart rate measuring apparatus according to  claim 1 , wherein the first electrode is attached to the fixed world and the second electrode is attached to the holder and spaced from the first electrode, the capacitance of the electrical motion sensor being based on a distance between the first electrode and the second electrode. 
     
     
       10. The heart rate measuring apparatus according to  claim 9 , wherein the second electrode, attached to the holder, moves relative to the first electrode upon movement of the holder relative to the fixed world. 
     
     
       11. The heart rate measuring apparatus according to  claim 10 , wherein a change in the distance between the first electrode and the second electrode upon movement of the holder equally or proportionally changes the capacitance of the electrical motion sensor to the heart rate and/or heart rate variation. 
     
     
       12. The heart rate measuring apparatus according to  claim 1  wherein:
 the holder is a bed, a mattress, a cushion, a crib or an incubator adapted for the subject to lie horizontally; and 
 the motion sensor is adapted to sense the force of the aortic arch impulse of an aorta of the subject in a horizontal direction relative to the ground rather than in the vertical direction using the motion sensor. 
 
     
     
       13. A method, adapted for measuring a subject's heart rate and/or heart rate variation, comprising:
 operatively connecting a motion sensor to a holder adapted for carrying at least a portion of a body part of the subject lying or resting on the holder; 
 moving the holder at least partly in a horizontal direction relative to the fixed world; 
 measuring a capacitance signal using of a capacitor including first and second electrodes, the capacitor being associated with the motion sensor to quantify a movement of the subject at least partly in a horizontal direction relative to the fixed world upon movement of the holder relative to the fixed world, at least one of the first and second electrodes being movable relative to the other of the first and second electrodes. 
 
     
     
       14. The method according to  claim 13 , further including:
 measuring a capacitance signal using an oscillator circuit associated with the capacitor and outputting-is a frequency signal that is modulated by the heart rate. 
 
     
     
       15. The method according to  claim 13 , further including:
 holding at least a portion of a body part of the subject in a suspended manner to allow the horizontal movement of the body part. 
 
     
     
       16. The method according to  claim 13 , wherein a movement of the subject in the horizontal direction relative to the fixed world alters a distance between first and second electrodes of the capacitor, thereby altering the capacitance of the capacitor. 
     
     
       17. The method according to  claim 13 , further including:
 relaying information about the subject's heart rate and/or heart rate variation to a user via a monitoring system. 
 
     
     
       18. The method according to  claim 13 , wherein a movement of the holder relative to the fixed world moves the second electrode, attached to the holder, relative to the first electrode. 
     
     
       19. The method according to  claim 18 , wherein a movement of the holder changes a distance between the first electrode and the second electrode, thereby equally or proportionally changing the capacitance of the electrical motion sensor to the heart rate and/or heart rate variation. 
     
     
       20. A heart rate measuring apparatus for measuring a subject's heart rate and/or heart rate variation, comprising:
 a holder configured to carry at least a portion of a body part of the subject lying on or resting against the holder, the holder including a suspension member for allowing at least partial movement of the holder in a horizontal direction relative to the fixed world, and 
 an electrical motion sensor operatively connected to the holder, the electrical motion sensor including a capacitor with an electrical capacitance, the electrical motion sensor including a first plate attached to the fixed world and a second plate attached to the holder and spaced from the first plate such that the second plate is movable relative to the first plate, 
 wherein the electrical motion sensor is adapted to measure a signal generated by a movement of the subject at least partly in the horizontal direction upon movement of the holder relative to the fixed world. 
 
     
     
       21. The heart rate measuring apparatus according to  claim 20 , wherein the capacitance of the electrical motion sensor changes equally or proportionally to the heart rate and/or heart rate variation upon movement of the second plate relative to the first plate. 
     
     
       22. The heart rate measuring apparatus according to  claim 20  wherein:
 the holder is a bed, a mattress, a cushion, a crib or an incubator adapted for the subject to lie horizontally; and 
 the electrical motion sensor is adapted to sense the force of the aortic arch impulse of an aorta of the subject in a horizontal direction relative to the ground rather than in the vertical direction using the electrical motion sensor.